LANSING — The Michigan Civil Rights Commission on Monday directed an agency to continue investigating complaints of discrimination based on sexual orientation and gender identity, days after the state attorney general declared the basis for the probes to be invalid because state law does not protect LGBT people from discrimination.

The board reiterated its support for a statement, which it issued in May, interpreting the word "sex" in the state's 1976 civil rights law to include sexual orientation and gender identity. Attorney General Bill Schuette, a Republican gubernatorial candidate, had issued an opinion Friday saying the commission overstepped.

He said "sex" refers to the biological differences between males and females — not sexual orientation or gender identity — and only the Legislature or voters can expand the law to protect LGBT citizens.

"The Michigan Civil Rights Commission is an independent, constitutionally created and established body," Agustin Arbulu, director of the Department of Civil Rights, said in a statement Monday. "The Commission is not bound by the opinion of the Attorney General. The only recourse is for the courts to determine if issuing the interpretive statement was within the scope of the commission's authority, and that is the appropriate venue for resolving this issue. Until that time, the Department will continue to carry out the directive of the Commission."

Schuette spokeswoman Andrea Bitely countered that attorney general opinions, while not the same as legal rulings, are binding on state agencies unless reversed by a court. She cited a 1971 state Supreme Court decision.

"Our position is based also on the AG's constitutional status as the state's chief law enforcement officer, and attorney for all executive departments and agencies," she said.

Democrats, however, question whether state departments must adhere to attorney general opinions, saying agencies are empowered to interpret laws that lawmakers have charged them with enforcing. Democrats say that the 1971 ruling cited by Schuette's office is not a precedent and point to other high court decisions suggesting the extent to which an agency is bound by an attorney general opinion is an open question.

As of last week, the state had received eight LGBT-based complaints since it began accepting them in May — some of which are under investigation.